1. Field of the Invention
The present invention relates to an airbag device in which bolt parts of a retainer which is caused to retain an inflator by clamping and are caused to protrude from a case through an airbag, so that nuts are fastened thereonto to thereby fix the inflator and the airbag to the case by making use of the retainer.
2. Related Art
Conventionally, in the airbag device that is configured as has been described above, the inflator, which is formed into a cylinder shape, is retained by the retainer, which is formed into a cylindrical shape, by clamping a plurality of clamping portions which are provided at a plurality of locations lying around the circumference of the retainer such that the inflator is housed in the interior of the retainer, and thereafter, the retainer is housed within the airbag such that bolt parts are caused to protrude therefrom. Furthermore, the airbag is housed within the case with the bolt parts caused to protrude from a fixing wall portion of the case, so that nuts are fastened onto the bolt parts to thereby fix the inflator and the airbag to the case (refer to, for example, JP-2003-205814).
In the conventional airbag device, however, the clamping work is necessary for the retainer to retain the inflator, leading to an increase in the number of manhours for assembling the airbag device.
Normally, since the inflator includes an igniter which ignites a gas generating agent which is filled in an interior thereof, needing to be handled within a facility satisfying the fire-safety standards, there has been a demand for a construction for this type of knee protection airbag device in which an airbag which is folded with only a retainer housed therein is housed in a case in advance, and thereafter, an inflator is mounted on the case, rather than housing an airbag which is folded with a retainer which is provided on an outside of an inflator housed therein in the case together with the inflator.
Further, in another conventional knee protection airbag device, the nut is fastened onto the bolt part which protrudes from a bottom wall portion of the case which is formed into a bottomed box shape which is opened on a rear side thereof, so as to fix the inflator to the case. This inflator is fixed to the case such that a connector side end portion thereof protrudes from a passage hole formed in a circumferential wall portion of the case. In addition, the inflator is circumferentially held to thereby be retained by the retainer by clamping a plurality of clamping portions provided at a plurality of locations lying along a circumferential direction of the retainer such that the inflator is housed in an interior of the retainer from one end thereof where a gas discharge port is provided (refer to, for example, JP-2004-50932).
In such the conventional knee protection airbag device, however, since the inflator is held and retained by the retainer on an outer circumferential surface thereof with an end face of the other end thereof to which the connector is connected not retained, when inflation gas is discharged from the gas discharge port provided at the one end of the inflator, with an intention to increase the output, there is caused a risk where the inflator moves along an axial direction thereof in such a manner that a portion thereof which lies to the end where the connector is connected largely protrudes to the outside of the case from the passage hole, and there still remains a room for improvement in suppression of the movement of the inflator.